The Story Behind That Incredible Photo of Denver's Colossal Cloud

Denver's not a piddling place – the city-county has 634,000 residents and 155 square miles of high-plains real estate, making it Colorado's largest 'burg. But stack it alongside this colossal cloud that materialized Saturday afternoon, and it looks like an itsy-bitsy base camp below an Everest of roiling smoke.

Here it is in panorama:

Greg Thow took these photos from the roof of his building near Sports Authority Field. "I've never seen that type of cloud before, to be honest, and my view has been solid here for several years," says Thow, the 49-year-old camera samurai behind Denver Digital Photography. And he's not likely to see one like it again: Even in the much-plumbedrealm of cloud photography, this one stands out as a rare stunner. Expect to see it on many weatherheads' lists for Best Photo of 2013.

Around the time Thow took the shot with a zoom lens, storms were pounding the northern part of the state with furious winds and hail. But the weather in Denver was relatively clear. "It was very windy, but with blue skies everywhere," he says. Looking east, however, he noticed a blotch on the horizon that "kept getting bigger and bigger" until it loomed over the city like a tremendous toadstool.

Thow produced these images with little digital trickery – they're "virtually straight out of camera" – and sent them to a local weather expert. Since then, the floating dreadnaught has accumulated a fawning audience on Facebook, where people have compared it to "nuclear fallout," swore that a "giant space ship is hiding in there" and stated, simply, "are you f'ing kidding me with this." The cloud even garnered a shout-out from Marshall Shepherd, president of the American Meteorological Society, who speculated that it "may be upslope related," meaning that moist air flowing up the nearby mountains might've cooled rapidly to become a monster mass of visible water.

Huge clouds exploding in the distance is not an everyday occurrence in Denver, Thow says. During an average year, the city sees "lots of superbrief, superintense thunderstorms, which is okay because we also have 280 days of sun." But 2013 is shaping up to be a "crazy" weather year, he predicts. That's good news for his oeuvre, which is already loaded with intense shots like the ones you see below. Looking at them, it's easy to believe Thow's claim that even a "chimpanzee could take good photos in a state this beautiful":